Plug with separable protection cap



Sept. 9, 1958 w. KOBLER ET AL PLUG WITH SEPARABLE'PROTECTION CAP FiledDec. 27. 1954 INVENTORS WWW 7 mm 7 ,Jmmm# United States Patent PLUG WITHSEPARABLE PROTECTION CAP Werner Kobler and Victor Kobler, Zurich,Switzerland Application December 27, 1954, Serial No. 477,756

Claims priority, application Switzerland September 17, 1954 1 Claim.(Cl. 339-36) The present invention relates to plug structures con nectedby means of flexible cables to electrical apparatus, where the plug bodysupports a separate protection cap for sensitive apparatus parts, andmore particularly to such plug structures where the plug body is ofoblong cross-section permitting connection with a socket having sunkcontacts.

In a known execution of such a plug the protection cap is made integralwith a sliding sleeve enclosing the insulating body completely and beingslidably guided thereon. The protection cap can thereby be displacedfrom a :position of use, in which it is situated in the vicinity of theend of the insulating body carrying the contact pins, into a nonoperative position in which it will not obstruct connecting of the plugto a socket having sunk contacts. The arrangement is thereby such thatthe removal of the protection cap or sliding sleeve respectively fromthe insulating body is not possible without disconnecting the latterfrom the electrical cable. This is often considered a disadvantage.

One object of the present invention is to provide a plug having aprotection cap, in which this cap is easily removable from theinsulating body without the necessity of disassembling any partsthereof.

A further object of the invention is to provide such a plug having aprotection cap which is slidably arranged on the insulating body andwhich, because of being made of elastic material and of being providedwith an open face, can be snapped out of engagement with the insulatingbody for removal from the latter.

Accordingly the protection cap on the insulating body can be displacedfrom a position of use, in which it is situated in the vicinity of theend of the insulating body carrying the contact pins, into a nonoperative position, at the end of the insulating body facing away fromthe contact pins, in which it will not obstruct connection of the plugto a socket havig sunk contacts. On the other hand the protection capcan be removed from the insulating body if desired.

In one preferred embodiment of the plug according to the presentinvention, the protection cap extends at substantially right angles fromone end of a guide portion of resilient material, which on its sidefacing away from the protection cap is provided with a groove havingrelieved side faces, the cross-section of which is similar to thecross-section of the insulating body slidably guided in this groove.Removal of the protection cap from the insulating body is effected inthis case by slightly straddling the sleeve portions limiting thegroove.

In order that the invention may be better understood and put intopractice one embodiment of the invention is hereinafter described by wayof example with reference to the accompanying drawing; showing thisembodiment in a perspective view.

The plug shown has an insulating body 1 which carries contact pins 2 ina known manner. The insulating body is of generally oblong cross sectionas is necessary for certain specified sockets (not shown) havingrecessed contacts. The insulating body suitably consists of a hardinsulating material for instance synthetic material. The plug shownfurther has a protection cap 3 extending at right angles away from thewider side of the insulating body which protection cap serves for theprotection of a sensitive part of the electrical apparatus such as thecutter head of an electrical dry shaver (not shown). The protection capis made integral with a slide 4 and extends at substantially rightangles therefrom. Slide 4 and protection cap 3 consist of resilientmaterial, for example, of soft rubber. At the wider side of the slide 4of oblong cross-section facing away from the protection cap a dove,tailed groove 5 extending normally thereto, is provided, itscross-section being equal to the cross section of the insulating body.Towards the free end of the .slide the groove is narrower and formsstops 7 for the insulating body 1 slidably guided in the groove withoutobstructing the passage for the cable 6 between the stops 7. The drawingshows the protection cap in operative position in the vicinity of thecontact pins 2. It can however be displaced towards the rear end of theinsulating body (non-operative position) such that it will no moreprevent insertion of the contact pins into the sunk contacts of thesocket. On the other hand the protection cap can be moved forward on theinsulating body to such an extent over the contact face side of thelatter till the stops 7 at the rear end of the groove 5 abut against theinsulating body. The length of the groove is suitably chosen such thatthe contact pins will be completely covered in this forward position ofthe protection cap.

On the other hand the slide 4 together with the protection cap 3 can beremoved from the insulating body 1 by slightly straddling the slide atits rim portions limiting the groove 5.

We claim:

A plug structure for connecting an electrical apparatus to a currentsupply, said apparatus having a sensitive apparatus part, said plugstructure including a plug body, a protection cap of resilient materialfor covering and protecting said sensitive part, a guide portion madeintegral with said protection cap and having a groove formed therein ofa size and shape slidably to accommodate said plug body, said groovehaving an open end and side permitting bodily separation of said plugbody from said guide portion of said protection cap.

References Cited in the file of this patent UNITED STATES PATENTS2,261,979 Domizi Nov. 11, 1941 2,350,048 Kobler May 30, 1944 2,383,031Wilson Aug. 21, 1945 2,490,580 Colla Dec. 6, 1949 2,729,797 Kobler etal. Jan. 3, 1956 Patented Sept. 9, 1958'

